TGFB1 and infection: Interestingly, in infected STAT3 KO mice, TGF-β expression was not significantly increased (1.50 ± 0.35 fold, P = 0.2766) 10 days after infection, in contrast to the raised expression level in infected WT mice (2.33 ± 0.37 fold, P = 0.0087) (Figure 1(b)).